How to write a code for atleast check one check box in PHP .

Question

 i have four check boxes ..i would like to validate for use can select at least one check box ...

 

 so how can i write a code for this  using bootstrap validator. 

<label for="remember" class="">

<input type="checkbox" class="" name="chk_interest[]" value="Food">

Food</label>

&nbsp;

<label for="remember"><input type="checkbox" class="" name="chk_interest[]" value="Blood" >

Blood</label>

&nbsp;

<label for="remember"><input type="checkbox" class="" name="chk_interest[]" value="Money" >

Money</label>

&nbsp;<label for="remember">

<input type="checkbox" class="" name="chk_interest[]" value="Organ" >

Organ</label>